You can make a genjutsu and warp reality to where you can.
That was my point, but there are very likely strong downsides.
The first is that its not really us doing the detailwork, or even the Beast. There is just too much raw information involved in making a single sunflower seed, too much for anything short of a god, so clearly something else is at play. We provide an outline, a stencil of what we want, and let the universe flow in and find the pattern that makes the most sense.
What makes the most sense to the universe in those places we don't, can't define would very much involve our rolling dice with
very high stakes. What happens when you plant that sunflower seed? Did you really fully conceptualize what a sunflower is and does down to the last detail? No: You just pictured the seed. This could end poorly with a human body.
The second is that the power, in extreme applications, seems to have a corrosive effect. A trained, hardened S-Class Jonin
had to take a sanity roll just by being witness. Just seeing something strictly material can't do that so I have to assume this is like fucking around with Warhammer's Warp, even if we are personally protected by effectively being a hereditary Daemonhost. Again, convincing the universe to drop its plans for a given chunk of itself and go with your idea instead.
Especially if what you ask for is impossible, like with the hawk. You start risking your acting like Missingno from Pokemon, a living buffer overflow error.
So, yeah, messing with Hagoromo and Kaguya-level conceptual bullshit is scary.